Spinodal instability growth in new stochastic approaches

TL;DR

This paper introduces new stochastic models to better describe spinodal instability growth in fermionic systems, addressing limitations of mean-field approaches by incorporating fluctuations to capture fragmentation mechanisms.

Contribution

The paper develops novel stochastic approaches that improve the mean-field response modeling of instabilities, enhancing understanding of spinodal fragmentation at the threshold.

Findings

Enhanced modeling of instability growth in fermionic systems.

Improved description of spinodal fragmentation mechanisms.

Addressed limitations of pure mean-field models.

Abstract

Are spinodal instabilities the leading mechanism in the fragmentation of a fermionic system? Numerous experimental indications suggest such a scenario and stimulated much effort in giving a suitable description, without being finalised in a dedicated transport model. On the one hand, the bulk character of spinodal behaviour requires an accurate treatment of the one-body dynamics, in presence of mechanical instabilities. On the other hand, pure mean-field implementations do not apply to situations where instabilities, bifurcations and chaos are present. The evolution of instabilities should be treated in a large-amplitude framework requiring fluctuations of Langevin type. We present new stochastic approaches constructed by requiring a thorough description of the mean-field response in presence of instabilities. Their particular relevance is an improved description of the spinodal fragmentation mechanism at the threshold, where the instability growth is frustrated by the mean-field resilience.